Comparative risk of adverse outcomes associated with nonselective and selective antimuscarinic medications in older adults with dementia and overactive bladder.

OBJECTIVE: The differential muscarinic receptor selectivity could cause selective antimuscarinics to offer advantages over nonselective agents with respect to adverse effects. The objective was to examine the comparative risk of falls/fractures and all-cause hospitalizations among older adults with dementia and overactive bladder (OAB) using nonselective and selective antimuscarinics METHODS/DESIGN: A retrospective cohort study design was conducted among older patients with dementia and OAB using incident antimuscarinics. The primary exposure was classified as nonselective (oxybutynin, tolterodine, trospium, and fesoterodine) and selective (solifenacin and darifenacin). Cox proportional-hazards regression using inverse probability of treatment weighting (IPTW) evaluated the risk of falls/fractures and all-cause hospitalizations within 6 months of nonselective and selective antimuscarinic use.

RESULTS: The study cohort consisted of 13,896 (76.9%) nonselective and 4,179 (23.1%) selective antimuscarinic incident users. The unadjusted falls/fractures rate was 27.14% (3,772) for nonselective and 24.55% (1,026) for selective users (p-value< 0.01). The unadjusted all-cause hospitalizations rate was 24.14% (3,354) for nonselective and 21.58% (902) for selective users (p-value <0.01). The IPTW models did not find a significant difference in the risk of falls/fractures (Hazard Ratio [HR] 1.03; 95% Confidence Interval [CI] 0.99-1.07) and risk of all-cause hospitalizations (HR 1.04; 95% CI 0.99-1.08) between nonselective and selective antimuscarinics. Several sensitivity analyses corroborated the main findings.

CONCLUSIONS: The study did not find a differential risk of falls/fractures and all-cause hospitalizations in older adults with dementia and OAB using nonselective and selective antimuscarinics. More research is needed to understand the role of pharmacodynamics and pharmacokinetics in the safety profile of antimuscarinics in dementia.